Here is my original arduino-based IR Lap Timer. It responds to an AIM beacon code. The display is in hundredths of seconds, with 4-digits allowing a maximum lap time of 99.99 seconds (no decimal point is displayed). However, the device will rollover and continue to count beyond 99 seconds. An ATmega328 version is capable of storing approximately 250 laps (168 is good for 125 laps).

1. Take note in the picture of the hole (barely visible) on the left side of the enclosure. The hole is for the IR detector. As depicted, the Timer will respond to beacons located to the left of the device. The Timer can be flipped upside down in order to respond to beacons to the right of the device. Toggling the power switch within the first 5-seconds of power-up will cause the display to invert.

2. Holding the button down during power-up will enter the ‘erase memory’ mode. This will cause the device to alternate between ‘0000’ and ‘8888’. Releasing the button when ‘0000’ is displayed will erase the memory. Conversely, releasing the button when ‘8888’ is displayed aborts the erase function.

3. Pressing the button during the first 5-seconds of power-up will allow one to increment the ‘ignore beacon duration’. The user has the option to select between 10 through 120 seconds (in 5 second increments).

4. Finally, at any other time the button can be pressed to step through the lap times stored in memory.

5. During the 5-second power-up period, the device will display the number of laps stored in memory, or the software version (currently 1001) if no laps are stored.

9 Responses to Arduino IR Lap Timer

Great project. I have just built my own version using an LCD screen rather than severn segment displays so it can display the lap count and the delta time from the previous lap. Your example was a great help and some of your coding ideas were most useful. I’ve also added an SD card aswell to record each lap (csv file so very easy to load onto PC). I use this during 24 hour racing when lap numbers can exceed 1000.

Great idea with the LCD screen, as the 7-segment is very limiting. I was going for the small size (kart vs. car), but after playing with it, I think your version is better. I’m glad you were able to get some inspiration from my code.

I have documented the build but now need somewhere to post it and the code. Somethings i still need to finish – Battery life, needs to last 24hrs, so i’m going to try 3 x 14500 li-ion 2000mAh. Make the device rain proof (British weather) and how to mount to steering wheel. I need to have this working ready for my next 24hr kart race at the end of August.

Ok I’ve started a blog documenting my timer. Its not fully finished but I’ve posted my code for bothe the IR Beacon and the timer. This was my first project so there’s probably so improvements to be had in my coding but it works which is the most important thing. Over the next couple of weeks i’ll add some more info to the blog including photo’s, it’s still a work in progress but i’m getting there

Here is the first part of my contribution to the world of lap timers. Nothing innovative in this version – EEPROM Storage, 4 button interface for menu scrolling and set up. My system is for optional use with rc cars so i wanted to make lap reviews between setup changes a bit more useable, I also added a loud buzzer. With 19 corners in a 20 second lap the only useful feedback is sound. One buzz for a captured lap and two if its a session best, I keep saying it, but its amazing how much harder you will drive to get that second buzz.